A163509 Take n written in binary. Replace the leftmost run of 1's with just a single 1. a(n) is the decimal equivalent of the result.

1, 2, 1, 4, 5, 2, 1, 8, 9, 10, 11, 4, 5, 2, 1, 16, 17, 18, 19, 20, 21, 22, 23, 8, 9, 10, 11, 4, 5, 2, 1, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 16, 17, 18, 19, 20, 21, 22, 23, 8, 9, 10, 11, 4, 5, 2, 1, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

Example

29 in binary is 11101. Replace the three 1's on the left of the binary representation with one 1, getting 101. a(29) is the decimal equivalent of the result, which is 5.

Maple

A163509 := proc(n) bdgs := convert(n, base, 2) ; while op(-1, bdgs) = op(-2, bdgs) do bdgs := subsop(-1=NULL, bdgs) ; od: add( op(d, bdgs)*2^(d-1), d=1..nops(bdgs) ) ; end: seq(A163509(n), n=1..120) ; # R. J. Mathar, Aug 07 2009

Mathematica

Table[FromDigits[Flatten[Join[{1}, Rest[Split[IntegerDigits[n, 2]]]]], 2], {n, 80}] (* Harvey P. Dale, Jul 17 2014 *)

Crossrefs

Sequence in context: A371015 A090077 A229763 * A161399 A318479 A053985

Adjacent sequences: A163506 A163507 A163508 * A163510 A163511 A163512

Keyword

base,look,nonn

Author

Leroy Quet, Jul 29 2009

Extensions

More terms from R. J. Mathar, Aug 07 2009

Status

approved